Azure Traffic Manager polls my site every few seconds

I am using Azure Traffic manager to manage an end-point for my web site.

Traffic manager polls a web page on my site to confirm that it is "Online"

When I look at my website logs it is getting polled by Traffic Manager from 2 separate IP addresses and at a rate of a hit every 3 seconds.  Sometimes it gets 2 hits in a second.

My question is how can I change the polling rate?

Many thanks for your help.

Paul C